Photocatalytic coatings are known in the art. These coatings commonly include a film of titania on a substrate. A great deal of research has been done with a view toward providing photocatalytic coatings that have desirable low-maintenance properties. Desirable low-maintenance properties include self-cleaning properties, hydrophilic properties, etc. The pursuit of low-maintenance window coatings, in particular, has been an active field of exploration.
It would be desirable to provide a photocatalytic coating with an underlayer that would enhance the low-maintenance properties of the coating. Additionally or alternatively, it would be desirable to incorporate into the photocatalytic film itself additional materials which would enhance the low-maintenance properties of the coating.